While heat development, for example of a high-economy, performance-optimized diesel engine, can be very low on the cylinder crankshaft housing, this low heat development in no way applies to “hot zones” such as manifolds, turbochargers, catalytic converters, etc. Due to the more and more compact construction of engines, components which are not thermally “compatible” are increasingly being placed in close proximity to one another. Accordingly, heat-sensitive assemblies, such as sensors, fuel lines, pressure cells, body parts, etc., must be protected against adjacent thermal engine components. The situation is exacerbated by the compact structure in that the high packing density of the assemblies constricts the cooling air flow in the engine compartment. Noise abatement measures can also contribute to this high packing density. Thus, for example, plastic bottom plates, designed to reduce the emission of noise from the engine compartment to the roadway, under certain circumstances can produce effective insulation with which heat is enclosed in the engine compartment. Catalytic converters, due to their phased high surface temperature, are considered to be among the heat sources which certainly may necessitate the use of protective shield barriers. One typical example of this need is design measures such as positioning the catalytic converter close by the manifold. This design principle, which performs the function of rapid heat-up of the catalytic converter reducing emissions in the cold start phase, shifts a major source of heat into the engine compartment, where numerous assemblies are crowded in a tight space. One reason for the growing importance of shielding components, such as heat shields, is the trend toward use of thermoplastics. The light and economical materials with their exceptional moldability are rapidly becoming common in the engine compartment, but require special attention with respect to ambient temperatures at the application site relative to other thermal engine parts (“New materials and development tools for heat protection”, in MTZ Dec. 2001, Vol. 72, pp. 1044 ff).
EP-A-1 298 365 discloses a metallic cylinder head gasket with a gasket sheet, which has at least one combustion space opening as a through opening The gasket unit which has at least two layers of metal sheet. The first layer of metal sheet is provided with at least one bead which is elastically deformable vertically and which encloses the combustion space opening. The second layer of metal sheet is provided with at least one deformation limiting device which encloses the combustion space opening and which limits deformation of the bead.
WO 01/96768 discloses a cylinder head gasket made as a flat gasket with at least one metallic layer in which at least one through opening (combustion space opening) is formed. It or at least one of the metal layers is made at least in particular areas in the form of corrugated or sawtooth profiling around the respective combustion space opening. At least the layer in which the profiling is made due to the required very high elasticity limits, has to be formed of a spring steel. The profiling has a deformation limitation device for an additionally formed bead.
In the known solutions described above, heat-insulating or acoustic-insulating component shielding and sealing of fluid-carrying installation spaces, also in gaseous form, are effected separately from one another. This separation means that shielding components in the form of heat shields perform the function of an independent component for acoustic and heat insulation. Optionally, multilayer sheet metal gasket structures are used especially in the area of cylinder head configurations to seal the fluid-carrying spaces. The known solutions are therefore characterized by a corresponding diversity of parts, resulting in increased production and installation costs.